1. Field of the Invention
This invention relates to computer software and systems used in the design of electronic components and more particularly to a database structure contained within an integrated circuit analyzing computer which reduces the amount of storage memory required to contain database analysis results.
2. Description of the Background Art
An integral step in the design and production of integrated circuits involves the computer analysis of the Integrated Circuit (IC) design to verify that each of the geometrical design rules required for effective fabrication of the components is satisfied. These design rules include such parameters as the minimum feature size and the minimum distance between components. Analysis of these circuits has become increasingly difficult over the past decade as the number of electronic devices included on a single integrated circuit is counted in the millions. It is not uncommon for analysis of a complex integrated circuit to take many hours of computation time and require hundreds or thousands of megabytes of storage. Much effort in the past has been devoted to finding ways of performing this analysis more efficiently.
The large storage requirements of a typical IC database affect the cost of analysis in a variety of different ways. First, the memory requirements themselves impose constraints on the size of the integrated circuit that can be analyzed. Although memory costs continue to fall and are expected to do so in the future, the cost of storing data is a major element in the overall computational economics, since memory requires space, power, thermal management, archiving, maintenance and capital investment. Second, large databases require more processing time. Ultimately, each byte of data contained in a memory space affects the speed with which other bytes may be accessed and processed. As a mapped memory space increases, the processor requires increasing quantities of address data to locate any particular byte. It also follows that data in a database which is read and processed sequentially, requires more processing time as the database size increases. Finally, as database sizes increase, more expensive hardware architectures are required to deal with the increased memory space.
Clearly, smaller databases are computationally less expensive and more efficient to operate. In order to improve the efficiency of analyzing IC databases, a method and system is needed which reduces the database storage requirements.